Seal-bearing agitator drives



April 15, 1958 A. STRATIENKO ET AL 2,830,801

SEAL-BEARING AGITATOR DRIVES Filed Dec. 28, 1956 s Sheets-Sheet 2 I I I r I, l/

4' INVENTORJ Andrew Srrcnienko Henry' Dowie McCullough April 1953 A. STRATIENKO awn. 2,830,801

SEAL-BEARING AGITATOR DRDIES 3 Sheets-Sheet 3 FIG.5

Filed- Dec. 28, 1956 FIG.6

Andrew Strctienko Henry Dpwie Mc Cullough mm M ATTY United States Patent SEAL-BEARING AGITATOR DREVES Application December 28, B56, Serial No. 631,101

11 Claims. (Cl. 259-122) This invention relates to agitators or mixers having mixing or agitating assemblies that are motor-driven or driven by other prime movers such as steam turbines, and

more particularly to those mixing vessels operating under either pressure or vacuum. For such vessels, there must be supplied some mechanism on the agitator shaft at the point where it enters the mixing vessel to prevent leakage at this point and to aid in the maintenance of the desired pressure or vacuum conditions in the vessel. A mech anism frequently used is usually referred to as an end face mechanical seal, and there are a number of these on the market that can be purchased as units adapted to be applied encirclingly to the agitator drive shaft, and to be removed therefrom in case replacement is needed.

Such a mechanical seal is essentially a precision instrument, which requires delicate handling of component parts during assembly in order to assure best operation. It is possible to assemble mechanical seals piece by piece in the field under adverse conditions, but poor results have often been experienced. Further, when these seals become defective in operation and must be replaced in the field, it has oftentimes been necessary to remove a number of bulkier drive components in order to carry out the replacement procedure, which has obvious disadvantages from the standpoint of time consumption and-of labor costs. So one object of this invention is to devise means by which the mechanical seal unit can be unitarily applied to and removed from the drive shaft of the mix ing vessel without tedious and delaying Work at the mixing tank site.

Since the drive mechanism and its blade-bearing agitating shaft can be quite heavy, indeed usually too heavy to lift by hand, it is another object of this invention to devise a driving assembly and support for the shaft that renders unnecessary any special equipment for raising or lowering the shaft and its associated parts.

More particularly it is an object of this invention to make it possible with a minimum of effort to remove and replace the mechanical seal unit from the agitator shaft.

Still more particularly, it is an objectof this invention to devise the mounting for the shaft on the mixer vessel and the agitator drive therefor, with suitable supports, bearings, and lubricating seals, whereby the mechanical seal while on the agitator shaft can be freed from :encumbering components thereabove thus enabling the operator to disengage the seal from the shaft and remove it without need of any sort of external lifting equipment.

Still another object is to devise means whereby the shaft can be uncoupled from its drive and lowered while still in its original alignment to an annular support carried by the housing for the drive to provide a free space between the drive and the end of the lowered shaft to permit the mechanical seal unit to be slipped upwardly along and over the end of the shaft, and thus removed from the housing. This object is broad enough to include means for permitting the replacement of the mechanical seal by a reverse procedure.

I 2,530,301 Patented Apr. 15, v1958 A more specific object is to devise an arrangement whereby the shaft can be dropped under controlled conditions by means of long enough threaded bolts, and whereby subsequently after the mechanical seal has been replaced, the shaft can be raised by a reverse rotation of those threaded bolts, thus rendering unnecessary any special external shaft-lowering or shaft-raising equipment, and this can be accomplished without any re-aligning of the shaft and its drive being required, since previously aligned shaft components are returned to original positions.

These objects, and indeed others that will appear hereinafter, can be realized by an embodiment of this invention having an apertured housing encircling a drive shaft and an agitator shaft rising from the mixing vessel on which latter are remova-bly mounted in rising relationship a unitary mechanical seal, a roller-bearing enclosing casing, and connecting means between the lower end of the drive shaft and the top of the agitator shaft made up of three superposed parts of which the top part is a flanged half coupling secured to the drive shaft and the bottom part is a similar but reversed flanged half coupling from which the agitator shaft is supported While the intermediate part is a sleeve having top and bottom flanges whose top flange has screw-threaded bolts connecting it to the top part and whose bottom flange has long screwthreaded bolts connecting it to the bo tom part with the long bolts being long enough to permit lowering of the bottom part and the agitator shaft it supports. Means for limiting the descent of the lowered agitator shaft are provided between the base plate of the apertured housing and the agitator shaft to permit the agitator shaft to be lowered sufliciently to enable the operator to remove the intermediate part of the connecting means between the drive shaft and the agitator shaft through an aperture of the housing. With the agitator so lowered, the other parts threaded or otherwise secured onto the agitator shaft can then sequentially be slid upwardly and removed from the shaft and the housing, including especially the unitary mechanical seal, since that is the element that will need replacing.

To replace the parts, the new, or repaired unitary n1echanical seal is first applied encirclingly to the agitator shaft and slid down into position, next the roller-bearing assembly is mounted on the agitator shaft and slid into position and secured, next the lower part of the connecting means is mounted on the agitator shaft and the top of that shaft secured thereto, then the intermediate. part of the connecting means is emplaced with its top flange bolted to the lower flange of the top part, and finally, the long screw-threaded bolts are put in place between the lower flange of the intermediate part and the top flange of the lower part, whereupon upon screwing up these long bolts, the agitator shaft is raised off its seat from its lowered position to be restored to its original operable position connected to the drive-shaft. All this is done while allowing the agitator shaft to be returned to its original aligned condition and no special lifting equipment or special tools are required.

As this invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, the present embodiment is therefore illustrative and not restrictive, since the scope of the invention is defined by the appended claims rather than by the description preceding them, and all changes that fall. within the metes and bounds of the claims or that form. their functional as well as conjointly cooperative equivalents, are, therefore, intended to be embraced by those claims.

in the drawings:

Fig. l is a view in elevation of the present invention mounted on the top of a mixing tank or pressure vessel and connected with a power delivering mechanism;

Fig. 2 is a view corresponding to Fig. 1 but showing the structure rotated approximately 90 and showing the housing for the drive coupling in longitudinal section with the coupling, bearing and mechanical seal structure shown in elevation;

Fig. 3 is a longitudinal section on an enlarge-d scale through the housing, the drive coupling and bearing, showing the power delivering shaft, the agitator shaft and the mechanical seal in elevation;

Fig. 4 is a longtiudinal section through the housing and showing the first stage in the operation of disconnecting the power delivering shaft from the agitator shaft in preparation for removing the agitator shaft mechanical seal;

Fig. 5 is a view corresponding to Fig. 4 and showing 7 upper end of the agitator shaft 23 and which is here the second stage in the operation of removing the mechanical seal wherein the intermediate coupling has been removed;

Fig. 6 is a view corresponding to Figs. 4 and 5 and showing the third stage wherein the lower half-coupling has been removed from the agitator shaft in preparation for the removal of the shaft bearing;

Fig. 7 illustrates the final stage wherein the agitator shaft bearing has been removed and the mechanical seal is shownin dotted lines removed from the agitator shaft preparatory to being withdrawn through the housing window.

Referring now more particularly to the drawings, the numeral 10 generally designates a standard or conventional power transmission gearing or gear reduction unit through which rotary power is transmitted from a prime mover such as an electric motor or the like, not shown, which is coupled with the shaft 12 which leads into the housing and is connected with the gearing therein. This reduction unit it) is of well known construction and accordingly no detailed illustration or description of the same is be-.- lieved to be necessary to the proper understanding or" the present invention. The mechanism It) has a power output shaft which is designated 14 and which usually extends, as shown in Fig. 3, through a seal which is generally designated 16, and a mounting annulus 18, the seal housing being secured to the housing 10a by bolts and the mounting annulus 18 is also secured to the gear reduction housing by bolts 21, all as shown in Fig. 3.

The numeral 22 designates, the top portion of a mixing tank or pressure vessel which is here shown in broken lines and in which is housed the mixer or agitator which is connected with the power delivering shaft 14 of the gear reduction mechanism.

The structure embodying the present invention and which is designed as hereinbefore stated to facilitate the removal from the agitator shaft 23 of the conventional mechanical seal, without the necessity of using external lifting equipment, is generally designated 24. This structure includes an elongate housing 25, of generally cylindrical shape, to the lower end of which is secured a flange 26 having a central opening 27. This housing is mounted upon a base flange 29 which in turn mounts upon the open top of the mixing tank or pressure vessel 22, which vessel is conventionally equipped with a mounting flange 22a for the reception of securing bolts 28 which pass through apertures in the mounting or base plate 29. The base flange which is in the form of a plate 29 which is fitted between the plate 26 and the pressure vessel flange 22 has a central opening 30 through which the agitator shaft 23 extends upwardly into the housing 25. This base flange 29 is here shown as having the securing bolts 28 passed therethrough, whereby the parts are securely locked or clamped together, but it is to be understood that other means may be employed for securing the housing to the base flange, as by means of threaded bolts that do not pass through the base flange. The base flange 29 supports the mechanical sealing unit which encircles the shown in side elevation and generally designated 31. This sealing unit, or mechanical seal, is secured to the base flange by the cap screws 32 which are accessible, as here inafter pointed out, from the interior of the housing 25 so that they may be removed to release the seal 31 and permit it to he slid upwardly on the agitator shaft for removal and replacement.

The gear reduction unit 10 is secured to the top end of the housing 25 by means of the plate 18 which, as shown, is welded or cast into or upon the top of the housing so as to form a fixed part thereof for the support of the unit 10. When the gear reduction unit is mounted upon the top end of the housing, as shown, the power delivering shaft 14 of the unit will be spaced in axial alignment with the agitator shaft 23.

The upper portion of the housing 25 is provided with a number of relatively large windows or openings 33 through which the parts of the coupling between the shafts 14 and 23 are removed.

Within the lower portion of the housing 25 there is secured a bearing supporting collar 34 the opening 35 of which is coaxial with the shafts and has the upper end of the agitator shaft extended therethrough as shown. This opening also is of suflicient diameter to permit the movement upwardly therethrough on the agitator shaft 23, of the mechanical seal 31 when the same is to be removed so that the seal can be taken out, in the manner hereinafter described, through one of the windows 33.

Below the collar 34, the wall of the housing has openings 33a of suitable size to permit introduction of necessary tools for the loosening and removal of the cap screws 32.

As shown, the agitator shaft 23 extends upwardly into the housing a substantial distance, terminating at its upper end above the lower edges of the window openings 33 for the purpose which will become apparent in the following description of the operation of removing the agitator shaft mechanical seal.

The shafts 14 and 23 are coupled together for unitary rotation by the coupling unit which is generally designated 36. This unit comprises an upper half-coupling 37 consisting of a sleeve 38 and an integral flange 39, a lower half-coupling which is generally designated 40 and which consists of a sleeve 41 and a flange 42, and an intermediate coupling spacer piece which is generally designated 13 and which comprises a sleeve portion 44 having upper and lower flanges 45 and 46, respectively.

The upper half-coupling 37 receives in the sleeve 38 the lower end of the shaft 14 to which it is locked by the pin 47 which passes transversely through the shaft and the sleeve as shown.

The lower half-coupling 40 has the interior of the sleeve 41 tapered as shown to fit down on the tapered upper end 2311 of the agitator shaft 23 and the face of the flange 42 is recessed as indicated at 48 to receive a cap plate 49 which is secured by the cap screws 50 to the top end of the agitator shaft 23 whereby to support the shaft 23 from the coupling unit.

The two half-couplings are joined together by the intermediate coupling spacer piece 43 to form the full or complete coupling unit 36. The upper flange 45 of the coupling piece 43 is connected with the flange 39 of the tophalf-coupling by bolts 51, the nuts 52 of which are threaded upon the lower ends of the bolts against the under face of the flange 45.

The lower flange 46 of the coupling piece 43 is secured to the flange 42 of the lower half-coupling by relatively long bolts 53 which pass upwardly and receive on their upper ends the nuts 54 which bear upon the inner side of the flange 46 in opposition to the nuts 52 of the upper 'bolts 51. These bolts 53 are materially longer than the 'bolts 51 and function as lowering and suspension means for the agitator shaft 23 in the process of removing the mechanical seal 31 as will be hereinafter set forth and 2,sso,sei

theyare also employed to draw the shaft 23 upwardly into position again after the mechanical seal has been replaced.

The upper end portion of the agitator shaft 23 above the seal 31 passes through a bearing assembly and hearing encasing box, the bearing assembly being generally designated 55 and the encasing box for the hearing assembly being generally designated 56.

The bearing encasing box comprises a pan-like lower portion 57 which is fitted into the opening 35 of the collar 34 where it is suspended by the flange 58 which rests upon the collar as illustrated. The collar 34 has threaded radially therethrough and through the wall of the enclosing housing 25, one or more set screws 59 which engage the wall of the pan 57 to secure it firmly in position.

The bottom of the pan 57 has a central opening through which the agitator shaft 23 passes and in this opening is fitted a grease seal 60 which encircles the shaft.

The top of the box 56 comprises a centrally apertured cover 61 having a central opening in which is secured a grease seal 62 through which the agitator shaft 23 passes and this cover is secured to the top edge of the pan by the cap screws 63, as shown. The bearing assembly 55 is fitted within the pan 57 with sufficient looseness to allow axial movement and is of a standard or conventional construction which includes a bearing adapter 64, which is fitted around the agitator shaft 23 and within the inner face of the bearing assembly and which is tightly maintained in position upon the shaft 23 by a lock ring 65. Upon the removal of this lock ring 65 the adapter 64 is loosened sufficiently to permit the bearing assembly to he slid upwardly and off of the end of the agitator shaft 23, together with the box enclosing the bearing assembly, after the box is released by the loosening of the set screw 59. v

The bearing box 56 is tightly closed by the cover 61 and the lower portion of the box or the pan 57 extends below the collar 34 and the bearing and forms a receptacle for oil or grease.

The mechanical seal 31 which is secured below the bearing and the bearing box upon the base flange 29 is, as hereinbefore stated, of conventional or well known construction. This seal is of the end face mechanical type and the components thereof are all encased within a housing 31a which is flanged as shown and secured by means of this flange and the cap screws 32 to the base flange 29.

The internal construction of the seal which is generally designated 31 may be of any one of a number of forms such, for example, as the mechanical shaft seal shown in Patent 2,723,868. Accordingly, it is to be understood that the specific internal character of the seal is not material to the working of the present invention and for this reason no detailed illustration of the same is made. It is only required that the seal be of the proper type to maintain a fluid-and gas-tight joint with the agitator shaft 23 so as to permit the desired rotary motion of the shaft without permitting the passage of fluids or gases from the tank or pressure vessel at the location where the agitator shaft enters the vessel.

One feature of this fluid seal resides in the provision of a drive sleeve 66 which tightly encircles the shaft and has assembled thereon the components of the seal which are located within the casing 31. The upper end of this drive sleeve can be secured to the shaft by various means such as encircling by a clamping lock ring 67 which is provided with a cap screw 68 for contracting the ring around the sleeve and tightening the sleeve on the shaft to rotate therewith. Between the top of the drive sleeve 66 and the lock ring 68 a retaining snap ring 69 may be located which encircles the drive sleeve and is interposed between the sleeve 66 and the lock ring.

Beneath the mechanical seal 31 there is fixed in the opening 30 of the base flange 29 a support collar 70 which is of somewhat greater internal diameter than the 6 overall diameter of the'shaft 23 which extends therethrough. This support collar has at its lower edge an inturned or inwardly projecting flange 71.

Cooperating with the support collar 70 is a suspension collar 72 which encircles the shaft and is firmly secured thereto in a suitable manner and this suspension collar may lie within the supporting collar 71 and is encircled at its top edge by the outwardly projecting flange 73 which, as shown, also may lie entirely within the supporting collar 70 and above and in spaced relation with the flange 71 when the agitator shaft is in operative connection with the shaft 14 through the medium of the coupling unit 36.

When the shafts 14 and 23 are operatively coupled together it will be seen that the upper end of the agitator shaft 23 lies adjacent to the plane of the meeting faces between the flanges 42 and 46 and the cap screws 50 which secure the plate 49 to the upper end of the shaft 23 may project above the surface of the flange 42 of the lower half-coupling 40. Also it will be noted that there is suflicient space between the lower end of the sleeve portion 41 of the lower half-coupling 40 and the top or cover 61 of the bearing box 56 to permit the lowering of the shaft 23 to the proper extent to bring the flange 73 of the suspension collar to rest upon the flange 71 of the supporting collar. This spacing is important in the operation of separating the shafts for the removal of the mechanical seal 31.

In describing the operation of removing the mechanical seal, reference will be had to Figs. 3 to 7 of the drawings. As noted, the intermediate coupling spacer piece 43 between the upper and lower half-couplings 37 and 40 is secured to these half-couplings by the bolts 51 and 53, the bolts 5'3 being of extra length as shown and hereinbefore stated.

The first step in connection with the operation of removing the mechanical seal after, of course, stopping the operation of the mechanism, is to loosen the cap screw 68 which removes the compression of the lock ring upon the mechanical seal drive sleeve 66 so as to permit sliding movement of the agitator shaft 23 therethrough. The next step is to loosen the nuts 54 upon the long bolts 53 which will permit the agitator shaft 23 together with the lower half-coupling 46 to move downwardly as illustrated in Fig. 4, to the point where the suspension collar flange comes to rest upon the flange of the supporting collar as is also shown in Fig. 4. The entire weight of the agitator shaft and the mixing impeller attached thereto is now taken upon the assembly or, in other words, is taken by the base flange 29.

It is now possible to completely unbolt and remove the intermediate coupling spacer piece 43 by removing the nuts from the bolts 51 and completing the removal of the nuts 54 from the bolts 53 so that the coupling spacer piece 43 can be taken out through one of the windows 33, as shown in Fig. 5. After taking out the coupling spacer piece 43 the cap screws 59 can be removed so as to facilitate removal of the plate 49 by which the upper end of the shaft 23 is attached to and held upon the lower half-coupling 40. This now permits the sliding upwardly from the upper end of the shaft 23 of the lower half-coupling 49 so that the structure now appears as illustrated in Fig. 6.

Access can now be had to the upper half or cover 61 of the bearing box or housing so that by removing the cap screws 63 the cover 61 can be taken off. This permits the rotation of the lock ring 65 which secures the hear ing adapter 64, loosening the latter so that it may be removed. By then backing out the set screws 59 the entire bearing assembly is released and can be removed from the collar 34 by sliding it up on the agitator shaft so that it may be taken out through one of the windows 33.

Access is now had to the mechanical seal. As shown in Fig. 7 with the bearing assembly and the encasing box removed, the mechanical seal after having the cap screws 32 withdrawn to detach it from the base flange 29, may be readily slid up on the shaft 23 to the position shown in broken lines in Fig. 7 where it is free of the upper end of the agitator shaft and may then be withdrawn through a window of the housing. Necessary repair work can now be done upon the mechanical seal while the agitator shaft is securely suspended. The operation of replacing the mechanical seal and other parts is, of course, directly reversed from the procedure described for removing the parts. Accordingly it is not believed that a detailed statement of the manner of replacing all of the parts is required. It will be seen, of course, that in the operation of removing the parts referred to, the long bolts and the nuts thereon function as lowering means until the suspension and supporting collars come into coupled relation and in the reverse operation it will be seen that after the lower half-coupling 40 has been replaced upon the upper end of the shaft 23 and secured thereto by the plate 49 and the intermediate coupling spacer piece 43 returned to its position between the upper and lower half-couplings 37 and 40 and the upper bolts 51 secured in place, the lower bolts and the nuts therefor may be employed for drawing the shaft up or raising it so as to disengage the suspension and supporting collars and also effect the necessary firm connection between the coupling spacer piece 43 and the lower half-coupling 40 thereby restoring the parts to the operative relation in which they are shown in Figs. 1 to 3.

The final step in the procedure is, of course, the tightening of the cap screw 68 to clamp the lock ring to the sleeve which forms a part of the unitary mechanical seal assembly.

In the illustration of the invention the long bolts employed for effecting the lowering of the shaft 23 and for later raising it have been illustrated as connecting the flange 42 of the lower half-coupling 40 with the lower abutting flange 46 of the intermediate coupling spacer piece. While this construction is preferred, it is to be understood that the arrangement of the long bolts 53 and the shorter bolts 51 may be reversed, if desired, without altering the efliciency of operation. In other words, it will be apparent that upon reversing the bolts the nuts for the long bolts 53, which will connect the flange 39 of the upper half-coupling with the flange 45 of the intermediate coupling spacer piece, may bear upon the top face of the flange 39 so that the shaft can be as easily and as efficiently lowered as then the long bolts are in the lowermost position shown in Fig. 3.

While in the illustration and foregoing description a particular type of gear reducer has been illustrated and described, it is to be understood that the invention is not confined in any manner to use with a gear reducer of the style here illustrated, as this gear reducer has been shown merely toillustrate a drive shaft for the agitator shaft and from which the agitator shaft is suspended. Obviously any type of gear reducer may be employed or the agitator shaft 23 may be coupled to and driven directly from a shaft of a prime mover without gear reduction mechanism if such an arrangement should be found feasible or desirable.

From the foregoing it will be seen that by the provision of the present invention the separation of a suspended driven shaft from a drive shaft may be easily and quickly effected for the removal of a mechanical seal such as that described without necessitating the employment of lifting apparatus or supporting apparatus outside of the mechanism itself, since such lifting and supporting means is incorporated in and forms an operative part of the coupling between the shafts.

We claim:

1. A coupling-bearing for a blade-bearing shaft for a mixing vessel having a top, a drive shaft, an agitator shaft rising from the mixing vessel, an apertured housing rising from the mixing vessel and supporting the drive shaft while having a base plate for attachment to the mixing vessel while encircling the agitator shaft, a unitary mechanical seal encircling the agitator shaft above the plate, and roller bearing means encircling the agitator shaft above the mechanical seal, with connecting means between the lower end of the motor drive shaft and the top of the agitator shaft made up of superposed parts of which the top part is a flanged coupling secured to the motor drive shaft and the bottom part is a similar but reversed flanged coupling from which the agitator shaft is supported while the intermediate part is a sleeve having top and bottom flanges whose top flange has screw-threaded bolts connecting it to the top part and whose bottom flange has long screw-threaded bolts connecting it to the bottom part, with the long bolts being long enough to permit lowering of the bottom part and the agitator shaft it supports until the descending shaft is stopped as hereinafter described to an extent permitting removal of the intermediate part from the housing through an aperture thereof followed by the sequential removal of the roller bearing means and finally the unitary mechanical seal and also permitting the restoration of those sequentially removed parts in reverse order, and means for stopping descent of the agitator shaft comprising an annular seat depending from the base plate of the housing while encircling the agitator shaft as well as a shouldered collar secured to the agitator shaft coactable with the seat when the agitator shaft is lowered for supporting the agitator shaft when so lowered and maintaining it in its original alignment.

2. Apparatus according to claim 1 wherein the top of the agitator shaft has a disc removably secured thereto from which disc the agitator shaft is supported from the bottom part of the connecting means.

3. A coupling-bearing drive for a blade-bearing shaft for a mixing vessel that has a top, a drive shaft, an agitator shaft rising from the mixing vessel and terminating in a flanged top, an apertured housing rising from the mixing vessel and supporting the drive for the drive shaft while being secured to a base plate for attachment to the top flange of the mixing vessel while encircling the agitator shaft, an annular seat encircling the agitator shaft depending from the base plate, a shouldered collar on the agitator shaft coactable with the seat when the agitator shaft is lowered, a unitary mechanical seal encircling the agitator shaft above the plate, lubricated anti-friction bearing means encircling the agitator shaft above the mechanical seal, a casing for the bearing means supported from the housing, an oil-seal bearing removable top for the casing, and connecting means between the lower end of the drive shaft and the top of the agitator shaft made up of superposed parts of which the top part is a flanged coupling secured to the drive shaft and the bottom part is a similar but reversed flanged coupling having a seat for supporting the top of the agitator shaft while an intermediate part has a sleeve having top and bottom flanges whose top flange has a set of screw-threaded bolts connecting it to the top part and whose bottom flange has a set of screwthreaded bolts connecting it to the bottom part, with the bolts of one set thereof being long enough to permit lowering of the agitator shaft far enough to permit its shouldered collar to be seatingly supported from the annular seat depending from the base plate of the housing, all whereby when the parts are unfastened the intermediate part of the connecting means is first removed through an aperture in the housing, then the lower part of the connecting means, next the top from the casing for the bearing positioned above the mechanical seal, then the bearing and lower casing, and finally the unitary mechanical seal, followed by a replacement of these parts in reverse order.

4. In apparatus of the character stated, a vertical driven shaft, a power shaft in spaced aligned relation with the top end of the driven shaft, a base plate having an opening through which the driven shaft extends, normally spaced elements between the driven shaft and base plate coacting upon a predetermined lowering of the shaft to support the driven shaft, a seal encircling the driven shaft and supported at the upper side of the base plate, a bearing unit encircling the driven shaft above the seal, means supporting the bearing unit, and a coupling means between and separable from the two shafts and suspending the driven shaft from the power shaft, said coupling means including means for effecting the said predetermined lowering of the driven shaft for the support of the driven shaft by the said coacting elements preliminarily to full removal of the coupling means, the spacing between the power shaft and the top end of the driven shaft being such after removal of the coupling means as to permit removal of the bearing unit and the seal from the top end of the driven shaft.

5. The invention according to claim 4, wherein the bearing supporting means comprises an annulus, an essentially cylindrical housing supported on the base plate and having the annulus secured therein, said annulus having an opening in which the bearing unit is mounted and of a size to permit the mechanical seal and housing to pass therethrough.

6. The invention according to claim 4, wherein the coupling means comprises a flanged upper-half-coupling, a flanged lower half-coupling, an intermediate coupling between the half-couplings and having flanges each abutting the flange of a half-coupling, and bolts connecting the abutting flanges, the said means for effecting the lowering of the driven shaft constituting extra long bolts between a half-coupling flange and the abutting coupling flange.

7. Apparatus of the character described for use with a mixing vessel having an opening in its top, a vertically disposed housing having a base plate adapted to rest upon and be secured to the opening in the top of said vessel, an agitator shaft rising from the vessel and passing through an opening in the base plate, a mechanical seal encircling the shaft and secured over said plate opening, a bearing encircling the shaft above the seal, means removably supporting the bearing in the housing, and a power delivering shaft supported upon the top of the housing in spaced and opposed alignment with the agitator shaft, with a coupling unit between the spaced shaft ends comprising an upper coupling flange carried by the power delivering shaft, a lower coupling flange carried by the agitator shaft and an intermediate elongate member having top and bottom flanges respectively abutting the upper and lower coupling flanges, means detachably securing said lower coupling flange on the agitator shaft, means detachably securing the upper coupling flange to the top flange of the intermediate member, means detachably securing the lower coupling flange to the bottom flange of the intermediate member, one of said detachably securing means being designed to effect the lowering of the agitator shaft in the operation of detaching one of the coupling flanges from an abutting flange of the intermediate member, an agitator shaft support carried by the base plate, a suspension means carried by the agitator shaft adapted to contact said support upon the said lowering of the agitator shaft whereby to suspend the agitator shaft from the support, and said housing having a wall opening of a size and in a position to facilitate removal 10 of the intermediate member and the removal successively from the agitator shaft and withdrawal of the lower coupling flange, the bearing and the mechanical seal.

8. The invention according to claim 7, wherein the means supporting the bearing in the housing comprises an annulus secured to the wall of the housing, a box removably mounted in the annulus and having a bottom and a removable top having openings through which the agitator shaft passes, and the bearing being secured to the shaft within the box.

9. The invention according to claim 7, wherein the means detachably securing one of the coupling flanges to an abutting flange of the intermediate member comprises long threaded bolts and nuts thereon.

10. The invention according to claim 7, wherein the means detachably securing one of the coupling flanges to an abutting flange of the intermediate member comprises long threaded bolts and nuts thereon, and the means detachably securing the lower coupling flange on the agitator shaft comprises a plate upon the end of the agitator flange extending over a part of the lower coupling flange and a threaded element passing through the last named plate and threaded into the end of the adjacent shaft.

11. A coupling-bearing drive for a blade-bearing shaft for a mixing vessel having a top, an agitator shaft rising from the mixing vessel, an apertured housing rising from the mixing vessel and supporting the device equipped with the drive shaft while being secured to a base plate for attachment to the mixing vessel while encircling the agitator shaft, a unitary mechanical seal encircling the agitator shaft above the plate, and anti-friction bearing means encircling the agitator shaft above the mechanical seal, with connecting means between the lower end of the drive shaft and the top of the agitator shaft made up of superposed parts of which the top part is a flanged coupling secured to the motor-drive shaft and the bottom part is a similar but reversed flanged coupling from which the agitator shaft is supported while an intermediate part has a sleeve having top and bottom flanges whose top flange has a set of screw-threaded bolts connecting it to the top part and whose bottom flange has a set of screw-threaded bolts connecting it to the bottom part, with the bolts of one set thereof being long enough to permit lowering of the bottom part and the agitator shaft it supports until the descending shaft is stopped as hereinafter described to an extent permitting removal of the intermediate part from the housing through an aperture thereof followed by the sequential removal of the bearing means and finally the unitary mechanical seal and also permitting the restoration of those sequentially removed parts in reverse order, and means for stopping descent of the agitator shaft comprising an annular seat depending from the base plate of the housing while encircling the agitator shaft as well as a shouldered collar secured to the agitator shaft coactable with the seat when the agitator shaft is lowered for supporting the agitator shaft when so lowered and maintaining it in its original alignment.

References Cited in the file of this patent UNITED STATES PATENTS 1,251,836 Stufllebeam Jan. 1, 1918 2,138,607 Larsen Nov. 29, 1938 2,203,404 Chace June 4, 1940 2,491,656 Goldman Dec. 20, 1949 

